A stand apparatus of the above kind is disclosed in U.S. Pat. No. 5,528,417. There, a stand apparatus for a medical-optical instrument is described which carries medical-optical equipment on a holding unit by means of a first parallel linkage pair and a second parallel linkage pair. The medical-optical equipment is accommodated on a front link of a parallel linkage pair which is connected to a crank-shaped clamp joint element via a third linkage unit. This clamp joint element is coupled to the holding unit via a further linkage unit. The clamp joint element causes the front linkage to maintain a vertical orientation in every position of the medical-optical equipment independently of the position of the first and second parallel linkage pairs.